Ultraviolet light source



Aug. Y1332, 1944.

W. O. PROUTY ULTRAVIOLET LIGHT SOURCE Original Filed March 23, 1 931Reissued Aug. 22, 1944 ULTRAVIOLET LIGHT SOURCE Willis O. Prouty,Hermosa Beach, Calif., assignor,

by mesne assignments, to Westinghouse Electric and ManufacturingCompany, New York, N. Y., a corporation util-Pennsylvania Original No.2,093,735, dated September 21, 1937,

Serial No. 524,649, March 23, 1931.

Application for reissue February 18, 1939, Serial No. 257,172 f (el.17e- 122) 11 Claims.

This invention relates to a source of ultraviolet light, such as can beused for therapeutic purposes.

This application is a continuation in part of my prior application,Serial No. 448,128, led

`April 28, 1930, and entitled Therapeutic light.

In the said prior application, I point out the disadvantages encounteredin ultra-violet light sources utilizing mercury arcs or carbon arcs.These disadvantages, in brief, can be summarized as follows: Suchdevices require excessive energy consumption; they become so hot thatartificial cooling is required;l and-due to such high temperatures,'itis dilicult to keep the tube sealed when tubes are used. Furthermore,the apparatus is bulky and costly. In mercury tubes, due to the hightemperatures of operation, there is a pronounced absorption effect ofthe ultra-violet emanations, making the device inefficient.

These disadvantages canbe almost entirely avoided When a high-voltagedischarge tube is used, having a filling of one or more of the noblemonatomic gases. Such gases are now in common use, and include neon,argon, helium, and krypton. Discharge tubes having such a lling, staycool and are compact.

Ordinarily neon or argon can be used as the gaseous lling, supplemented,although not necessarily, by the addition of a few drops of mercury toincrease the ultra-violet radiations. I have found that the intensity ofthese emanations can be still further materially increased byproportioning the discharge tube in a manner thatwill be morespecifically described hereinafter.

For example, in one series of comparative tests performed on a deviceincorporating my invention and a commercial mercury arc device, it wasfound that although the power consumed by my device was only aboutone-eighth that consurned by the mercury vapor device, yet my deviceemitted ultra-violet radiations in general much in excess of the mercuryvapor device. The comparison was made at definite wave lengths ofradiations; at wave lengths considerably above visibility, theintensities of the emanations from my device werevery much greater thanfrom the other device. Since the therapeutic effect of such short wavelengths is especially beneficial, it is seen that this feature is ofconsiderable importance.

Accordingly it is one of the objects of my invention to make it possibleto secure this intense radiation of ultra-violet light by the aid of aluminous discharge device.

My invention possesses many other advantages, and has other objectswhich may be made more easily apparent from a consideration of oneembodiment of my invention. For this purpose I have shown a form in thedrawing accompanying and forming part of the present specification. Ishall now Proceed to describe this form in detail, which illustrates thegeneral principles of my invention; but it is to be understood that thisdetailed description is not to be taken in a limiting sense, since thescope of my invention is best defined by the appended claims.

Referring to the drawing:

Fig. 1 is a side elevation of an ultra-violet ray device embodying myinvention;

Fig. 2 is a longitudinal, sectional view thereof;

Fig. 3 is a detail section taken along plane 3`3 of Fig. 2;

Fig. 4 is a detail section taken along plane 4--4 of Fig. 2; and

Fig. 5 is a detail view taken in general in the direction of the arrow 5in Fig. 2.

The source of ultra-violet radiations is shown as a tube II which isdoubled one or more times on itself. This tube is shown as provided atits extremities with the small internal electrodes I2 and I3, but otherforms of electrodes could be used if desired. This tube can be filledwith any of the noble monatomic gases or mixtures thereof to a pressureof a few millimeters of mercury, say from four to twelve millimeters. Afew drops of liquid mercury can also be inclosed inside the tube. Thistube is made from material that can readily pass the ultra-violet rays,such as quartz. The tube II can, furthermore, be kept comparativelysmall, its doubled length in most instances not exceeding 10 or 12inches, although the length of the tube II can be varied to suitconditions.

In order to obtain the best and most intense effects from the tube I I,its inner diameter should not exceed seven millimeters; the preferablevalue is about three or four millimeters. It should be` operated below acurrent consumption of 5() milliamperes, and a potential differenceacross it above 1G00 volts. Apparently the small diameter obviatesmaterial self-absorption ofthe rays, and the low current consumption,while suflicient to cause the gas to luminesce, yet serves to leave thetube I I cool enough to be readily handled by an operator withoutartificial cooling, inasmuch as its operating temperature is inherentlybelow C. which is but slightly above body temperature, and which, as iswell recognized from International Critical Tables, gives a mercurypressure of not more than 13 microns during operation of the device.

In order to house the tube II and provide terminals for connection tothe electrodes I2 and I3 I may utilize a casing I4. This casing may bemade from a casting such as aluminum. Its top portion may be generallycylindrical and is preferably formed with an. opening I5 through whichthe tube II can be exposed. In the present instance, the Width of theopening can be varied, as by a shutter IE which conforms K with theinterior surface of the casing, and which can be manipulated as by ahandle Il extending through a slot I8 in the back of the casing. Ifdesired the interior surface of this shutter can be polished to act alsoas a reflector.

In order to permit the tube IMI to be inserted into the casing I4 thereis provided a top opening I9. This opening can be closed by cover member20. In order to steady the tube I I this cover member may carry acushion or pad, such as 2|, 'made of sponge rubber or the like.

In theV present instancel the lower portion of frame I4 can beflattened, as indicated most clearly in Fig. 4. In this lower por-tiontherev is a large opening 22" that can be covered up by' cover plate 23.This cover plate can be fastened in place by screws 2.4.

Terminal block 25 can be accommodated in: the: lower portionofv thecasing and` can be held in place as by the aid of one or more screws26., This terminal block can be made of' any appropriate insulationmaterial. It carries a number of screws 2l, engaging theconductors 28,29'that lead to the electrodesy I2 and I3. The extremities of the tube II can be accommodated in shallow pockets, such as 30, 3l inthe frontface of the block 25.

The conductorsk 28 and 29 can extend downwardly below block 25. They canpass through the neck 32 tothe exterior, andarefshown in Fig. 2 ascarrying heavy insulation, forming the twin conductor 33.` A plug34 canbe used to. maintainthis conductor 3.3 in placein the neck 32.

In order further to supportY the tube. I I against dislodgement I mayutilize several turnsof asbestos rope 35 encompassing both bends of thetube II` near the lower portion thereof. Sponge rubber cushion 36 can befastened to the cover 23 (Fig. 4) for holdingV these extremities in thepockets 30, 3|.

For the application of the ultra-violet rays to a comparatively largesurface, the opening I5 can be used. The size of the opening can :beadjusted by manipulation of handle I'I, the hand of the manipulatorgrasping the lower portion of the-casing I4.

For more conned' treatment I can provide a tubular extension 39, at anangle to the casing axis, through which the upper part of the tube IIcan be exposed. If desired7 a supplementalv applicator coniining thearea treated still further, can be supported in extension 39. Oneexample of such applicators is indicated in Figs. 1, 2, and 5. Itincludes a quartz-rod 3l. This quartz rod is cemented in a metal collar38, which is adapted to be disposed near the tube II. In order tosupport the collar 38 detachably in this projection 39, this extensioncan be provided with a bayonet slot 40 for accommodating pin 4Iextending radially of. the collar 38.

In the present instance this applicator 3l is shown merely as a bent rodwhich is made of quartz, and which has the property of conducting theyultra-violet radiations from inside casing I4 to the extremity or tip 42of the rod, without substantial dispersion transverse to the rod. Thetip 42 of the applicator can therefore be directed against the localityto be treated.

I believe that the eiectiveness of this tube resultsA mainly from theysmall current consumption and small cross-sectional area. The small areaensures against interference and reabsorption or change of wave length,and the small cur- .rentrconsumptiom because it keeps the tube cool,

also contributes to the same end.

I claim:

l. In a device for producing ultra-violet radiations having a highintensity in the wave band from 2000 to 2540 Angstrom units, a tubecapable of passing such radiations, said tube having an internaldiameter no greater than seven millimeters,` a filling for the tube ofone or more noble monatomic gases, and means for impressing anenergizing potential diierence across the column of gas-.in the tube.

2. In a device for producing ultra-violet radia tions having a highintensity in the Wave` band from. 2000 to 2540v Angstrom units, a tubecapable off passing such radiations, said tube having an internaldiameter no greater than seven millimeters a filling for the tube of oneor more noble monatomicr gases, and means for impressing an energizing'potential dilerence across the column of'. gas inthe tube, to produce acurrent iiow therein not exceeding iifty milliamperes.

3. In a device for producing ultra-violet radiations having a high.intensity in the wave band from 2000 to 2540 Angstrom units, a tubecapable of passing such radiations, said tube: having an internaldiameter no greater than seven millimeters, a lling for the tube of oneor more noble monatomic gases., and means for impressing an energizingpotential differencefacross the column of gas* in the tube, saidpotential diierence being no less than one thousand volts.

4. In; a device for producing ultra-violet radiations having; a highintensity in the Wave band from 2000 to 2540 Angstrom units, a tubecapable of passing such radiations, said tube having an internaldiameter between three and four millimeters, a filling for the tube ofone or more noble monatomic gases, and means forl impressing anenergizing potential difference across the column of gasv in the tube,to produce a current flow therein not exceeding fifty milliamperes.

5. The process of producing ultra-Violet radiations having aV highintensity lying in the Wave bandV from 2000 to 2540 Angstrom units, bythe aid of a luminous column of noble monatomic gases, which comprisesenergizing said gas column, and confining the column to a diameter nogreater than seven millimeters.

6. The process of producing ultra-violet radiations having a highintensity lying in the wave band from 2000 to 2540 Angstrom units, bythe aid of a luminousv column of noble monatomic gases, which comprisesenergizing said gas column, and reducing self-absorption in the columnby restricting the diameter of the column.

7. The process of producing ultra-violet radiations having a highintensity lying in the wave band from 2000 to 2540 Angstrom units, bythe aid of a luminous column of noble monatomic gases, which comprisesenergizing said gas column, confining the column to a diameter nogreater than seven millimeters', and restricting the current flowthrough the column to a value not exceeding fifty milliamperes.

8. The process of producing ultra-violet radiations having a highintensity lying in the Wave band from 2000 to 2540 Angstrom units, bythe aid of a luminous column of noble monatomic gases, which comprisesenergizing said gas column, and confining the column to a diameter-betWeen three and four millimeters.

9. An ultra-violet lamp for producing ultraviolet radiations having ahigh intensity in the wave band of 2000 to 2540 Angstrom unitscomprising an envelope containing a, gaseous lling at a pressure of atleast 4 millimeters including mercury vapor and an inert gas, and meansfor impressing an energizing potential across said lamp to caus-eluminescence of said gaseous filling and to produce a current iiowtherein sufficient to maintain the operating temperature of said lamp atapproximately 50 C. whereby the mercury vapor is maintained at apressure not greater than 13 microns.

10. The method of operating an ultra-violet lamp for producingultra-violet radiations having a high intensity in the Wave band of 2000to 2540 Angstrom units and provided with an envelope containing agaseous filling including mercury vapor and an inert gas, which consistsin impressing across the lamp an energizing potential suicient to causeluminescence of the gaseous filling, and restricting the currentconsumption of said lamp to a value such that the operating temperatureofthe lamp is maintained at approximately 50 C. and thus cool enough tobe readily handled, and the mercury vapor pressure during operation ismaintained at approximately 13 microns.

1l. A discharge lamp for producing ultra-violet radiations having a.high intensity in the Wave band of 2,000 to 2,540 Angstrom unitscomprising an envelope containing a gaseous filling includingmercuryvapor and an inert gas, and means for impressing an energizing potentialacross said lamp to cause luminescence of said gaseous lling and toproduce a current flow therein suiiicient to maintain the operatingtemperature of said lamp at approximately 50 C. and the mercury pressureat approximately 13 microns.

WILLIS O. PROUTY.

